Rat hole drilling device



Nov. 7, 1950 Filed May 10, 1948 J. w. HICKERSON, sR

RAT HOLE DRILLING DEVICE 3 Sheets-Sheet l INVENTOR.

1] 052225 WEE/refs 017, 521

Nov. 7, 1950 J. w. HICKERSON, SR 5 5 RAT HOLE DRILLING DEVICE v Filed may 10, 1948 :5 Sheets-Sheet 2 f 1 T-I INVENTOR.

4/ 32) 5012253 Vl/Eckersazgfi' HISAG'E/VT NOV. 1950 I J. w. HICKERSON, SR 2,528,593

RAT HOLE DRILLING DEVICE Filed May 10, 1948 3 Sheets-Sheet 5 Patented Nov. 7, 1950 UNITED RAT HOLE DRILLING DEVICE James W. Hickerson, Sr., Archer City, Tex.

Application May 10, 1948, Serial No. 26,093

2 Claims.

This invention relates to improvements in Rat Hole Drilling Devices, and more particularly to rat hole drilling devices which may be attached to the floor of the derrick and allowed to remain there after the drilling of the rat hole has been completed.

In the rotary drilling art, it is desirable to drill an angular hole, which is known as the rat hole, at a spaced distance from the well in which the Kelly may be lowered while lowering and removing drill stem from the well. While these rat holes are only six or eight feet less in depth than the length of the Kelly joint, it is often a source of great inconvenience to drill these holes, especially when it is drilled with the conventional rotary table. Many rotary drillers prefer to have both a rat hole in which to lower the Kelly when not in use, and a mouse hole in which to lower lengths of drill stem after they have been coupled together preparatory to coupling the unit on to the drill stem to be lowered into the well during the drilling operation.

The present invention is adapted to readily drill both the rat hole and the mouse hole with convenience and speed, and without the usual annoyance of having to move heavy equipment from place to place. This present device is light in weight, sturdy in construction, and is particu-' larly adapted to the type work for which it has been designed.

The primary object of this type of drilling equipment is to provide a rat hole drilling device that may be driven from the conventional rotary table drive mechanism, and which is easy to install and to remove, when it is necessary to move from one location to another.

Another object in providing this equipment is to provide a rat hole drilling device that will permit the Kelly joint to be slidably passed therethrough, whilestill maintaining the Kelly joint at an angle and rotatably connected with the drive member of the rat hole drilling device, which drive member is attached to the device at the top thereof.

Rat hole drilling equipment of this character in use heretofore has been bulky and cumbersome, and it has been, as a rule, necessary to completely dismantle the machine to allow the Kelly joint to be passed therethrough, in order to drill the rat hole, and likewise dismantling i was required to remove the device from around the Kelly joint when the drilling of the rat hole was completed. Furthermore, in some of these machines, it was necessary to run the sprockets out of parallel alignment, which resulted in rapid wear on the drive chains.

With the present machine, the rat hole drilling device may be set in place, the Kelly joint, with a drill bit thereon, placed therethrough. The rat hole is then drilled, the drill bitremoved from 2 the Kelly joint and then the rat hole cased, all in an eflicient and expeditious manner.

The present rat hole drilling device is so constructed that it may be readily removed, as a unit, or it may remain in place, without hampering workmen or delaying the other drilling operations, after the rat hole has been completed.

An embodiment of this device is illustrated in the accompanying drawings, in which:

Fig. 1 is a diagrammatic side elevational view of a rotary well drilling machine, showing the rat hole drilling device in place, and with the Kelly joint having a drill bit thereon, shown to be in position for drilling the rat hole, a portion Fig. 5 is a sectional view taken on the line- 55, looking in the direction indicated by the arrows; on Fig. 4;

Fig. 6 is a plan view on a reduced scale of a drive member used in driving a fluted Kelly joint;

Fig. '7 is a perspective view, reduced in scale, of the drive sprocket, with a portion of the rotary table shown in elevation, and with parts broken away and shown in section to illustrate the details of construction;

Fig. 8 is an elevational view of a rat hole casing member showing a drill bit on the lower end thereof, with parts broken away and shown in section, and with parts of a well shown in section, and a portion of a rat hole rotary table shown in section to illustrate the relative position of the rat hole casing to the rotary table;

Fig. 9 is a top plan view of a modified form of drive bushing for driving a rat hole casing memher; and

Fig. 10 is a sectional view taken on the line l0! 0 of Fig. 8, looking in the direction indicated by the arrows.

With more detailed reference to the drawing, the numeral 1 designates a power unit for driving the draw-works 2 of a rotary drilling rig, which drilling rig has a mast pole or derrick 3 which extends upward and has a sheave 4 at the upper end thereof, over which sheave a cable 5 is adapted to pass for supporting the traveling I block 6. The traveling block supports the usual swivel l to allow'for the turning movementoi the Kelly joint 8 when said Kelly joint is engaged either with the rotary table 9, or with is adapted to fit within openings or rat hole Kelly drive member I3, in the case of a square Kelly, or, I3 in the case of a fluted Kelly. The holes l4 and I4 in the respective members I3-I3', are Slightly larger in cross section than the cross-section of the Kelly joint, thereby permitting a free sliding fit of the Kelly joint in the respective hole, even with the Kelly positioned at an angle. However, the fitting relation between the Kelly joint and the hole It or I4 in the bushing I3 or I3 is maintained sufficiently close as to insure a driving relation therebetween. The drive members I3 or I3 are formed in halves so they may be readily bolted to the upper portion of turn table I5 by means of bolts I6.

The rat hole drive member I3 has the edges of opening [4 therein rounded at I3a so that the Kelly when passing therethrough, is provided with a rounded bearing surface, the metal of which may be hardened if desired. With the drive member being split in halves, it may be readily removed and replaced by means of bolts I6.

The rat hole rotary table I5 is provided with an axial sleeved opening I'I, through which the Kelly joint is lowered. The rotary table I5 is attached to sleeve I! by means of bolts I8, which allows the ready removal thereof for assembly and repair. A sprocket I9 is welded, or otherwise secured, intermediate the length of the sleeve I1, and has a bearing race on either side thereof to receive bearings and 2|, respectively. These bearings are journaled within their respective housings 22-23, and a thrust bearing 24 is positioned below sprocket I9 so as to take the thrust load, when the drive bushing I2 rests upon the top of drive member I3.

In the use of a construction of this character,

the drilling of the rat hole is accomplished Without the necessity of removing the conventional'Kelly drive bushing. However, the work of either of the drilling operations is not impeded. Furthermore, the hole through the sleeve is sufiiciently large to allow the drill bit to be passed therethrough, so that'disassembly of the unit is unnecessary while positioning the bit for the drilling of or removing the bit from the rat hole, and it is also sufiiciently large to permit the rat hole to be cased therethrough.

The bearings 20 and 2I are lubricated through. their respective lubrication fittings 25 and 26, which extend to the outside of the respective housings. Appropriate lubricant seals 27, 28 and 29 are provided for the retention of lubricant around bearings 28, 2| and 24.

A torque arm 30 is provided to be attached to an ear 3|, which torque arm is positioned substantially in tangential relation to the lower frame 23 and is attached thereto. The torque arm 30 extends to and is in binding relation with the frame of the rotary table 9. With the torque arm positioned on a side of the frame and in substantially tangential relation therewith, and with the rat hole rotary table turning in the direction as indicated by the arrows, in Fig. 4, the torque from the rotary table will be transmitted to the torque arm, and to the framework of the rotary table 9, thereby relieving bolts 32 of strain.

The rat. hole drilling device is constructed so that it may be readily disassembled by the removal of bolts It, I8 and 33. The rat hole rotary table I5 is driven by sprocket I9 through chain 34, which chain 3 encircles a drive sprocket 35 that is integrally secured to squared drive bushing 33, which squared drive bushing is adapted to interfit with a square recess in the top' of rotary table 9, as will best be seen in Figs. 2 and 7. The drive sprocket and drive bushing 353% are respectively secured in the rotary table by a bolt 31 which passes therethrough and engages a crossbar 38, which cross bar extends across opening 39. in the lower portion of rotary table 9, and securely holds the drive sprocket and drive bushing in place.

It is preferable to have the rat hole rotary drilling device supported on legs 48 of the desired height, so that the chain 34 will align with sprockets I9 and 35, as indicated in Figs. 2'and 3. "These legs are secured at their lower ends to structural member ll, which may be bolted to the floor of the derrick by bolts 33.

The rat hole rotary table is so designed that the horizontal chain 34 may pass out at either end thereof, between the legs 4%) and frame member 23a, as indicated in Fig. 4.

In the operation of the rat hole drilling device, the power drive unit I is connected to the rotary draw works 2 by means of a conventional drive such as achain 3 i, or other suitable drive means, and the draw works, in turn, is connected to a drive shaft 9a on the rotary table 9, in the conventional'manner, such as'by sprockets and chains. and with the drive sprocket 35 secured in ,fixed relation therewith, and with the sprocket I9in alignment with sprocket 35, and with the chain 34 encircling these sprockets, the rat hole rotary table I5 will be rotated, upon the rotation of the rotary table 9, and with the'Kelly joint 8, having a drill bit secured to the lower end thereof, positioned within the rat hole rotary drive member I3, as'shown in Figs. 1 and 5, the Kelly joint is allowed to slide at an angle therethrough while being rotated. With the drill bit B, secured to the lower end of the Kelly joint, as stated, an angular hole, known as a rat hole, will be drilled, which hole may be cased if desired.

It is to be pointed out thatthe sleeve I! is journaled'within anti-friction bearings 2E-2I, and that the rotary table I5 is retained against longitudinal downward movement by'rneans-of thrust bearin 24. When the drilling of the rat hole has been completed, the Kelly joint 8 and the bit B may be removed throughthe sleeve IT, by removing the drive member I3, for the removal of the drive member I 3, the boltslt are removed. After the removal of the Kelly joint and the bit, the rat hole rotary table may be left in place or removed as desired. With the drive member I3 removed, the Kelly joint may. be placed in the rat hole or removed therefrom as desired, as it is for this purpose thatthe. rat hole has been prepared. The drive member I3 is not Thus the rotary table 9 may be rotated used after the rat hole drilling has been completed.

A modified form of drive bushing is shown in Figs. 8 and 9, which drive bushing is so designed as to rotate a joint of casing to which is aflixed a drill bit. This drill bit is slightly larger in diameter than the diameter of the casing. In some formations, such as quick sand, or the formation found in marine locations, it is neither practical nor expedient to drill a rat hole without casing it, as it would cave in as fast as it was drilled, and never be of any use as adepository for the Kelly joint.

With the present modification of the rat hole drilling mechanism, provision is made to efficiently provide the usual rat hole, in such formations as mentioned above, in which the casing will follow the bit to the bottom of the hole, where it can remain as long as the rat hole is in use, but, since the formation is soft. it can be readily removed, when the casing is pulled from the rat hole.

The rat hole is drilled with the same methods as are used in the drilling of the well, and provision is made for circulation of fluid for the lubrication of the cutting tool, and to wash up the cuttings.

With more detailed reference to the drawing, Figs. 8, 9, and 10, the numeral ll designates the inner sleeve of the rat hole rotary table, the axial opening of which sleeve is sufficiently large to admit the passing of a joint of casing therethrough at an angle as indicated in Fig. 8, and through a casing drive bushing 53, which casing drive bushing is bolted to flanged ring member I5, by means of bolts IS.

The bushing 53 is formed in halves and has a hole 54 therein, the edges of which hole are rounded, as will best be seen in Figs. 8 and 9. The bushing 53 has key-way 55 within the bore 54 thereof, as will best be seen in Figs. 8 and 9, which key-way inter-engages key members 56 on opposite sides of rat hole casing 52, as shown in Fig. 8. The key-way 55 also has rounded edges so as to enable the casing 52 to have universal action with respect to the bushing 53 while the casing is passing through the bushing as an angle, as indicated in Fig. 8, and at the same time maintaining driving relation between the bushin 53 and the casing 52.

The rat hole rotary table is driven in the manner as explained above, it is however, preferable to have the hole 54 in the drive bushing 53 larger than the outside diameter of the casing 52, so the casing may be received through the bushing, for universal action therewith as is best illustrated in Fig. 8.

It is preferable that the casing 52 be swaged at its lower end for connection with a bit 58, which bit is usually of the fish-tail type, as shown in Fig. 8. The bit 58 is slightly larger than the key on casing 52. This makes possible the drilling of a rat hole by means of the bit 58, which is sufiiciently large that the casing 52 follows the bit as it bores downward, and thus keeps the hole open and cased during and after the drilling operation.

In the normal drilling operation, fluid is circulated downward through the lower end of the swivel 1 and is discharged through opening 59 of bit 58, to flow upward around the outer walls of the casing 52. to the top of the well.

Upon completion of the rat hole 60, the bit 58 may be left at the lower end of the casing 52, and the swage nipple at the upper end thereof may be removed, to permit the insertion and removal of the Kelly joint.

It is to be understood that the casing may be left attached to the rat hole rotary table, or the rat hole rotary table may be removed from around the casing, as desired.

After the cased rat hole has served its normal purpose, the said casing, with the drill bit on the lower end thereof, may be pulled from the hole, and may be used for other drilling operations.

It is to be understood that this modification of the rat hole drilling mechanism applies particularly to sandy and soft formation, in which the casing of the rat hole is a necessity and not a matter of choice, in order to maintain the rat hole in operating condition during the drilling of the well. When the need for the rat hole no longer exists, the casing, with the bit thereon may be pulled from the hole, and the hole allowed to fill or cave as the formation indicates.

A mouse hole is drilled in a similar manner to the rat hole with either modification of the mechanism, but, as a rule, the mouse hole is drilled closer to the well, for obvious reasons.

While this invention has been described in some detail as to structure, in order to illustrate an operable form of the invention, it is to be understood that changes may be made in the details of construction without departing from the spirit of the invention as claimed.

Having thus described the invention, I claim:

1. In a rat hole drilling device for use with a rotary rig, a base, upright standards secured to said base and adapted to support a frame on the upper ends thereof, said frame having a bore therein adapted to receive a sleeve therethrough, said sleeve having a sprocket secured thereto, a second frame member having a bore therethrough adapted to fit around said sleeve and upon the first mentioned frame, said sleeve projecting upwardly and having an out-turned flange removably secured thereto, bearings journaled to the respective frames above and below said sprocket, said sleeve having a bore therein of suflicient size to receive a drill bit therethrough, a drive bushing positioned on top of said sleeve and secured to said flange, said bushing having a hole therethrough and being split so as to fit around a Kelly joint, the hole in said bushing being of approximately the shape of the cross-sectional area of said Kelly joint, said Kelly joint with said drill bit on the lower end thereof being adapted to pass through said hole in said sleeve to be engaged by said split bushing and rotated therewith, the edges of said bushing hole being rounded to permit the free sliding action-0f the Kelly joint thereon.

2. In a rat hole drilling device for use with rotary drilling rigs a base, upright standards secured to said base and adapted to support a frame on the upper ends thereof, said frame having a bore therein adapted to receive a sleeve therethrough, said sleeve having a sprocket secured thereto, a second frame member having a bore therethrough adapted to fit around said sleeve and to rest upon said first mentioned frame member, said sleeve projecting upwardly and having an out-turned flange removably secured thereto, anti-friction bearings journaled in the respective frames above and below said sprocket, said sleeve having a bore therein of sufficient size to permit the passing of a drill bit therethrough, a drive bushing positioned on top of said sleeve and secured to the top of said flange, said bushing having a hole therein, and said bushing being split so as to fit' around a Kelly joint, when a Kelly joint is positioned therethrough, said hole in said bushing 'being of substantially the samecross-sectional area as the cross-sectional area. of the Kelly joint but having the edges thereof rounded 5 so the Kelly joint may pass therethroughat an angle, but ma be engaged by said bushing and rotated therewith, a thrust bearing disposed below said sprocket for engagement therewith, said thrust bearing being secured to the lower of said 10 frame-members. 7

JAMES W. I-IICKERSON, SR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Summers Sept. 14, 1869 Heggem Jan. 31, 1911 Kline June 9, 1914 Thrift Sept. 13, 1927 Ackerman Oct. 4, 1938 Alexander et a1 Mar. 23, 1943 

